MENLO PARK, Calif. — Facebook said Wednesday that fake accounts and pages that likely have ties to Russia spent $100,000 in divisive political ads from June 2015 to May 2017 before the U.S. presidential election.

A total of 470 fake accounts and pages ran roughly 3,000 ads during that period, Facebook’s Chief Security Officer Alex Stamos wrote in a blog post.

Facebook found that these accounts had ties with one another and they “likely operated out of Russia.” The tech firm shut down these accounts and pages and has shared its findings with U.S. authorities.

The revelation by the world’s largest social network comes as Special Counsel Robert Mueller and congressional investigators are looking into Russia’s interference in the 2016 presidential election.

The U.S. Intelligence Community released a report in January that stated they had “high confidence” that the Russian government tried to help Trump get elected.

Donald Trump Jr. is also reportedly expected to testify behind closed doors Thursday before the U.S. Senate Judiciary Committee about meeting with a Russian lawyer claiming to have dirt on his father’s opponent, Democratic candidate Hillary Clinton.

Since Donald Trump won the 2016 presidential election, Facebook has been asked about Russia’s meddling in U.S. politics. The company was also criticized for not only doing enough to stop the spread of fake news.

Most of the political ads that Facebook discovered didn’t reference the U.S. presidential election, voting or a specific candidate.

But the ads and accounts “appeared to focus on amplifying divisive social and political messages across the ideological spectrum — touching on topics from LGBT matters to race issues to immigration to gun rights,” Stamos wrote.

The tech firm also broadly searched for ads that might have ties to Russia. In that review, about 2,200 ads — amounting to $50,000 in spending — were purchased from accounts that had U.S. Internet Protocol (IP) addresses but had a language set to Russian.

Facebook has been stepping up its fight against fake news and misinformation following the U.S. election, but the tech firm acknowledges there’s more to do.

“We know we have to stay vigilant to keep ahead of people who try to misuse our platform,” Stamos wrote. “We believe in protecting the integrity of civic discourse, and require advertisers on our platform to follow both our policies and all applicable laws.”